<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        var temp; //声明一个空变量
        var apple1 = ('青苹果');
        var apple2 = ('红苹果');
        temp = apple1; //给temp赋值1
        apple1 = apple2; //给apple1赋值Apple2
        apple2 = temp;
        console.log(apple1);
        console.log(apple2);
    </script>
</head>

<body>

</body>

</html>